Nucleotide sequence of rmpB, a Klebsiella pneumoniae gene that positively controls, colanic biosynthesis in Escherichia coli

Abstract

Production of colanic acid in Escherichia coli is regulated by two negative regulators, Lon and RcsC, and by two positive regulators, RcsA and RcsB. Two genes of Klebsiella pneumoniae, rmpA and rmpB, have been shown to positively control colanic acid synthesis in E. coli. While colanic acid production is activated by RmpA only in a lon strain of E. coli, a plasmid carrying both rmpA and rmpB can stimulate colanic acid synthesis in a Lon+ strain. In this work, we present the determination of the nucleotide sequence of rmpB and, on the basis of comparison of the predicted RmpA and RmpB sequences with those of RcsA, B and C and two-component regulatory proteins, we propose that RmpA acts as a transcriptional activator of the structural genes involved in colanic acid biosynthesis.